HTTPCLIENT-1123: Support for pluggable DNS resolvers.

Contributed by Alin Vasile <alinachegalati at yahoo dot com>


git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk@1165635 13f79535-47bb-0310-9956-ffa450edef68

RELEASE_NOTES.txt

@@ -1,8 +1,18 @@
-Changes since 4.1.1
+Changes since 4.1.2
+
+* [HTTPCLIENT-1123] Support for pluggable DNS resolvers.  
+  Contributed by Alin Vasile <alinachegalati at yahoo dot com>
 
 * [HTTPCLIENT-1120] DefaultHttpRequestRetryHandler#retryRequest should not retry aborted requests
   Contributed by Alin Vasile <alinachegalati at yahoo dot com>
 
+
+Release 4.1.2
+-------------------
+
+The HttpClient 4.1.2 is a bug fix release that addresses a number of non-critical issues reported 
+since release 4.1.1.
+
 * [HTTPCLIENT-1100] Missing Content-Length header makes cached entry invalid
   Contributed by Bart Robeyns <bart dot robeyns at gmail dot com>
 
@@ -32,6 +42,9 @@ Changes since 4.1.1
   do not correctly handle content streaming.
   Contributed by James Abley <james.abley at gmail.com> 
 
+* [HTTPCLIENT-1051] Avoid reverse DNS lookups when opening SSL connections by IP address.
+  Contributed by Oleg Kalnichevski <olegk at apache.org>
+
 
 Release 4.1.1
 -------------------

httpclient/src/main/java/org/apache/http/conn/DnsResolver.java

@@ -0,0 +1,52 @@
+/*
+ * ====================================================================
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ *
+ */
+package org.apache.http.conn;
+
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+
+/**
+ * Users may implement this interface to override the normal DNS lookup offered
+ * by the OS.
+ */
+public interface DnsResolver {
+
+    /**
+     * Returns the IP address for the specified host name, or null if the given
+     * host is not recognized or the associated IP address cannot be used to
+     * build an InetAddress instance.
+     *
+     * @see InetAddress
+     *
+     * @param host
+     *            The host name to be resolved by this resolver.
+     * @return The IP address associated to the given host name, or null if the
+     *         host name is not known by the implementation class.
+     */
+    InetAddress[] resolve(String host) throws UnknownHostException;
+
+}

httpclient/src/main/java/org/apache/http/impl/conn/DefaultClientConnectionOperator.java

@@ -53,6 +53,8 @@ import org.apache.http.conn.scheme.Scheme;
 import org.apache.http.conn.scheme.SchemeRegistry;
 import org.apache.http.conn.scheme.SchemeSocketFactory;
 
+import org.apache.http.conn.DnsResolver;
+
 /**
  * Default implementation of a {@link ClientConnectionOperator}. It uses a {@link SchemeRegistry}
  * to look up {@link SchemeSocketFactory} objects.
@@ -90,6 +92,9 @@ public class DefaultClientConnectionOperator implements ClientConnectionOperator
     /** The scheme registry for looking up socket factories. */
     protected final SchemeRegistry schemeRegistry; // @ThreadSafe
 
+    /** the custom-configured DNS lookup mechanism. */
+    protected final DnsResolver dnsResolver;
+
     /**
      * Creates a new client connection operator for the given scheme registry.
      *
@@ -100,6 +105,26 @@ public class DefaultClientConnectionOperator implements ClientConnectionOperator
             throw new IllegalArgumentException("Scheme registry amy not be null");
         }
         this.schemeRegistry = schemes;
+        this.dnsResolver = null;
+    }
+
+    /**
+    * Creates a new client connection operator for the given scheme registry
+    * and the given custom DNS lookup mechanism.
+    *
+    * @param schemes
+    *            the scheme registry
+    * @param dnsResolver
+    *            the custom DNS lookup mechanism
+    */
+    public DefaultClientConnectionOperator(final SchemeRegistry schemes,final DnsResolver dnsResolver) {
+        if (schemes == null) {
+            throw new IllegalArgumentException(
+                     "Scheme registry amy not be null");
+        }
+
+        this.schemeRegistry = schemes;
+        this.dnsResolver = dnsResolver;
     }
 
     public OperatedClientConnection createConnection() {
@@ -233,6 +258,10 @@ public class DefaultClientConnectionOperator implements ClientConnectionOperator
      * Resolves the given host name to an array of corresponding IP addresses, based on the
      * configured name service on the system.
      *
+     * If a custom DNS resolver is provided, the given host will be searched in
+     * it first. If the host is not configured, the default OS DNS-lookup
+     * mechanism is used.
+     *
      * @param host host name to resolve
      * @return array of IP addresses
      * @exception  UnknownHostException  if no IP address for the host could be determined.
@@ -240,7 +269,11 @@ public class DefaultClientConnectionOperator implements ClientConnectionOperator
      * @since 4.1
      */
     protected InetAddress[] resolveHostname(final String host) throws UnknownHostException {
-        return InetAddress.getAllByName(host);
+        if (dnsResolver != null) {
+            return dnsResolver.resolve(host);
+        } else {
+            return InetAddress.getAllByName(host);
+        }
     }
 
 }

httpclient/src/main/java/org/apache/http/impl/conn/InMemoryDnsResolver.java

@@ -0,0 +1,119 @@
+/*
+ * ====================================================================
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ *
+ */
+package org.apache.http.impl.conn;
+
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.util.Arrays;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.http.conn.util.InetAddressUtils;
+import org.apache.http.conn.DnsResolver;
+
+/**
+ * In-memory DNS resolver implementation with entries built using the
+ * {@link InMemoryDnsResolver#add(String, String) method}.
+ *
+ * Currently this class supports only IPv4 addresses.
+ *
+ */
+public class InMemoryDnsResolver implements DnsResolver {
+
+    /** Logger associated to this class. */
+    private final Log log = LogFactory.getLog(InMemoryDnsResolver.class);
+
+    /**
+     * In-memory collection that will hold the associations between a host name
+     * and an array of InetAddress instances.
+     */
+    private Map<String, InetAddress[]> dnsMap;
+
+    /**
+     * Builds a DNS resolver that will resolve the host names against a
+     * collection held in-memory.
+     */
+    public InMemoryDnsResolver() {
+        dnsMap = new ConcurrentHashMap<String, InetAddress[]>();
+    }
+
+    /**
+     * Associates the given IP address to the given host in this DNS overrider.
+     *
+     * @param host
+     *            The host name to be associated with the given IP.
+     * @param ip
+     *            IPv4 address to be resolved by this DNS overrider to the given
+     *            host name.
+     *
+     * @throws IllegalArgumentException
+     *             if the given IP is not a valid IPv4 address or an InetAddress
+     *             instance cannot be built based on the given IPv4 address.
+     *
+     * @see InetAddress#getByAddress
+     */
+    public void add(final String host, final String ip) {
+        if (!InetAddressUtils.isIPv4Address(ip)) {
+            throw new IllegalArgumentException(ip + " must be a valid IPv4 address");
+        }
+
+        String[] ipParts = ip.split("\\.");
+
+        byte[] byteIpAddress = new byte[4];
+
+        for (int i = 0; i < 4; i++) {
+            byteIpAddress[i] = Integer.decode(ipParts[i]).byteValue();
+        }
+
+        try {
+            dnsMap.put(host, new InetAddress[] { InetAddress.getByAddress(byteIpAddress) });
+        } catch (UnknownHostException e) {
+            log.error("Unable to build InetAddress for " + ip, e);
+            throw new IllegalArgumentException(e);
+        }
+
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public InetAddress[] resolve(String host) throws UnknownHostException {
+        InetAddress[] resolvedAddresses = dnsMap.get(host);
+        if (log.isInfoEnabled()) {
+            log.info("Resolving " + host + " to " + Arrays.deepToString(resolvedAddresses));
+        }
+
+        if(resolvedAddresses == null){
+            throw new UnknownHostException(host + " cannot be resolved.");
+        }
+
+        return resolvedAddresses;
+    }
+
+}

httpclient/src/main/java/org/apache/http/impl/conn/PoolingClientConnectionManager.java

@@ -47,6 +47,7 @@ import org.apache.http.pool.ConnPoolControl;
 import org.apache.http.pool.PoolStats;
 import org.apache.http.impl.conn.DefaultClientConnectionOperator;
 import org.apache.http.impl.conn.SchemeRegistryFactory;
+import org.apache.http.conn.DnsResolver;
 
 /**
  * Manages a pool of {@link OperatedClientConnection client connections} and
@@ -77,10 +78,17 @@ public class PoolingClientConnectionManager implements ClientConnectionManager,
 
     private final ClientConnectionOperator operator;
 
+    /** the custom-configured DNS lookup mechanism. */
+    private final DnsResolver dnsResolver;
+
     public PoolingClientConnectionManager(final SchemeRegistry schreg) {
         this(schreg, -1, TimeUnit.MILLISECONDS);
     }
 
+    public PoolingClientConnectionManager(final SchemeRegistry schreg,final DnsResolver dnsResolver) {
+        this(schreg, -1, TimeUnit.MILLISECONDS,dnsResolver);
+    }
+
     public PoolingClientConnectionManager() {
         this(SchemeRegistryFactory.createDefault());
     }
@@ -93,6 +101,20 @@ public class PoolingClientConnectionManager implements ClientConnectionManager,
             throw new IllegalArgumentException("Scheme registry may not be null");
         }
         this.schemeRegistry = schemeRegistry;
+        this.dnsResolver = null;
+        this.operator = createConnectionOperator(schemeRegistry);
+        this.pool = new HttpConnPool(this.log, 2, 20, timeToLive, tunit);
+    }
+
+    public PoolingClientConnectionManager(final SchemeRegistry schemeRegistry,
+                final long timeToLive, final TimeUnit tunit,
+                final DnsResolver dnsResolver) {
+        super();
+        if (schemeRegistry == null) {
+            throw new IllegalArgumentException("Scheme registry may not be null");
+        }
+        this.schemeRegistry = schemeRegistry;
+        this.dnsResolver = dnsResolver;
         this.operator = createConnectionOperator(schemeRegistry);
         this.pool = new HttpConnPool(this.log, 2, 20, timeToLive, tunit);
     }
@@ -119,7 +141,7 @@ public class PoolingClientConnectionManager implements ClientConnectionManager,
      * @return  the connection operator to use
      */
     protected ClientConnectionOperator createConnectionOperator(SchemeRegistry schreg) {
-        return new DefaultClientConnectionOperator(schreg);
+        return new DefaultClientConnectionOperator(schreg, this.dnsResolver);
     }
 
     public SchemeRegistry getSchemeRegistry() {

httpclient/src/test/java/org/apache/http/impl/conn/TestDefaultClientConnectOperator.java

@@ -0,0 +1,78 @@
+/*
+ * ====================================================================
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ *
+ */
+package org.apache.http.impl.conn;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+
+import org.apache.http.conn.DnsResolver;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class TestDefaultClientConnectOperator {
+
+    @Test
+    public void testCustomDnsResolver() throws Exception {
+        DnsResolver dnsResolver = mock(DnsResolver.class);
+        InetAddress[] firstAddress = translateIp("192.168.1.1");
+        when(dnsResolver.resolve("somehost.example.com")).thenReturn(firstAddress);
+
+        InetAddress[] secondAddress = translateIp("192.168.12.16");
+        when(dnsResolver.resolve("otherhost.example.com")).thenReturn(secondAddress);
+
+        DefaultClientConnectionOperator operator = new DefaultClientConnectionOperator(
+                SchemeRegistryFactory.createDefault(), dnsResolver);
+
+        Assert.assertArrayEquals(firstAddress, operator.resolveHostname("somehost.example.com"));
+        Assert.assertArrayEquals(secondAddress, operator.resolveHostname("otherhost.example.com"));
+    }
+
+    @Test(expected=UnknownHostException.class)
+    public void testDnsResolverUnknownHost() throws Exception {
+        DnsResolver dnsResolver = mock(DnsResolver.class);
+        when(dnsResolver.resolve("unknown.example.com")).thenThrow(new UnknownHostException());
+
+        DefaultClientConnectionOperator operator = new DefaultClientConnectionOperator(
+                SchemeRegistryFactory.createDefault(), dnsResolver);
+        operator.resolveHostname("unknown.example.com");
+    }
+
+    private InetAddress[] translateIp(String ip) throws UnknownHostException {
+        String[] ipParts = ip.split("\\.");
+
+        byte[] byteIpAddress = new byte[4];
+        for (int i = 0; i < 4; i++) {
+            byteIpAddress[i] = Integer.decode(ipParts[i]).byteValue();
+        }
+        return new InetAddress[] { InetAddress.getByAddress(byteIpAddress) };
+    }
+
+}